Nanotechnology, the ability to manipulate structures on an atomic level, has the potential to revolutionize our world. From creating artificial skin that allows the user to “feel,” to using nanoscopic algae “backpacks” to deliver chemotherapy treatment, it is a technological field that constantly breaks new ground. Exemplifying this, a new study in Nature Materials showcases the world’s smallest 3D lattice structure – one that is made of glassy carbon struts 500 times smaller than the width of a human hair.
A single lattice is roughly 10,000 nanometers across, meaning you could line up at least 150 on a single head of a pin. Lattices, like this record-breaking glassy one produced by a team at the Karlsruhe Institute of Technology (KIT) in Germany, can be used as load-bearing supports.
“Lightweight construction materials… are found everywhere in nature,” Dr. Jens Bauer, a researcher at KIT and lead author of the study, noted in a statement. “They have a high load-bearing capacity and small weight and, hence, serve as models for mechanical metamaterials.”
Despite the fact that this honeycomb lattice is incredibly small, it can withstand unbelievably high pressures – 1.2 billion newtons per square meter (roughly 174,000 pounds per square inch), to be precise. This is 12,000 times the pressure of the atmosphere. The only suitable comparison to this new lattice is diamond, another carbon-based lattice structure, which can withstand slightly more force at the equivalent size.
The individual struts themselves are even stronger, exhibiting material strengths of up to 3 billion newtons per square meter (roughly 435,100 pounds per square inch). These struts were printed out using a technique called 3D laser multiphoton lithography. During the process, a liquid resin ink is made to harden using a very powerful laser.
This laser forces the resin to absorb two photons at the same time; as this can only happen at the center of the beam, this method allows for extreme precision during printing. This means that solidification of the ink can happen at any depth, not just at the surface – and incredibly intricate structures, including this new carbon-based lattice, can be made.
Only diamonds, with their incredible mechanical strengths, are comparable to this new honeycomb, glassy carbon lattice. 123dartist/Shutterstock
In order for the lattice to be so small, however, a special “baking” process is also required. When the lattice has been 3D printed, it is exposed to temperatures of around 900°C (1,652°F) in a vacuum chamber. This causes all other elements other than carbon within the structure to become energetically excited and escape, while turning the carbon itself into a form of glass, hardening it as the overall structure shrinks by up to 80 percent of its original size.
In addition to being incredibly strong, this lattice is also highly electrically conductive, meaning that it could also be used as an electrode in a range of electrical equipment. It can actually be classified as a type of “metamaterial,” microscopic or nanoscopic structures designed to have novel mechanical and optical properties.
Metamaterials dynamically and quickly react to changing light, temperature or pressure conditions; they include prototype sonar cloaking devices on submarines that bend incoming sound waves around the hull, and computer circuitry that uses light, not electrons, to process and transmit data at incredible speeds.